Take this for what it is: the opinion of someone rolling on 33s, lol.
Nothing wrong with another set of 37s. The tons aren't a license to be stupid (every guy is born with that), but they would allow a bit more freedom with the go pedal in a tricky situation. Plus, 40s will make some of the boarderline obstacles into easy mode, and will make some of the really hairy stuff tantalizing, enticing you to try lines more likely to end in a roll or flop. Plus, the ease of just throwing on another set of 37s vs. getting out the sawzall and new bumpstops is a nice bonus.
But I could be totally wrong. Then again, you could sell the new-ish 37s when you inevitably decide you have to have 40s.